The Zero Waste Coffee Project

Where are we going next with coffee by-products?

What can we make out of coffee flowers, coffee leaves, and all of the coffee byproducts and coffee-related consumption waste?I had the good fortune to find out last week, October 15th/2021, during the CoffeeBy-products as Sustainable Novel Foods - Foods2021 E-Conference.

I am typing this blog a day after the session and I must admit that I've found the whole experience amazing – so much scientific knowledge was shared! Speakers from all over Europe presented research using a myriad of coffee varieties and their by-products collected from coffee-producing countries in ways that have the potential to expand uses for coffee by-products in groundbreaking ways.

The session began with Dr. Dirk W. Lachenmeier’s opening keynote, followed by Dr. Steffen Schwarz. Dr. Schwarz introduced the concept of coffee by-products and their applications. He further classified by-products utilization into three major classes:

1.    Alimentary uses: e.g.flour, syrup, tea and other beverages

2.    Materials: e.g.packaging, construction and clothing

3.    Energy production and fertilizers: e.g. biogas and compost

Dr. Lachenmeier then provided an update on sustainable income generation of coffee by-products as novel foods within the European Union. He started by explaining what the EU  considers as novel food. Lachenmeier then categorized the different by-products according to their status of approval within the EU for human consumption. He also outlined the process by which companies can obtain approval for such novel foods.

In the next sessions,each speaker focused on a specific by-product.

Starting with coffee leaf tea, Dr. Jörg Rieke-Zapp (Sanofi, Frankfurt) highlighted that coffee leaf tea is traditionally consumed in a number of coffee producing countries. He emphasized the additional income that farmers can gain from the sale of coffee leaves.

Next, Dr. Ennio Cantergiani presented on Cascara (coffee cherry tea),from the quality viewpoint. He outlined the production processes for both wet and natural processed Cascara, as well as the importance of good agricultural practices and critical control points. Additionally, he shared his own tentative cupping protocol for Cascara beverages. For me, there was a real 'aha!' moment as I was not aware that such a protocol existed.

Then, Prof. Harshadrai Rawel presented on wet-coffee processing production wastes, quality potentials, and value generating opportunities.He identified spent coffee (which also includes husk, pulp and silverskin) as a source of ingredients for cosmetics or the production of enzymes such as beta-glucosidase; but it can also be converted into raw materials for bio-ethanol production, activated carbon or for composting.

Prof. Dr. Maria Angeles Martín-Cabrejas discussed re-value generation of coffee parchment as a source of phenolic compounds and antioxidant dietary fiber. She outlined the effects of extrusion of coffee parchment on its chemical and functional properties. She concluded that coffee parchment has the potential to be a functional, low-calorie ingredient for dietary fibre enrichment in foods for regulating blood glucose.

The last coffee by-product topic was silverskin, the by-product created during coffee roasting. Both Prof. Maria Martuscelli and Ms.Vera Gottstein discussed its chemical characterization with special consideration of dietary fiber and heat-induced contaminants. They agreed that silverskin has a high potential for its use as an ingredient or additive in novel foods. However, further studies are required to come up with a formulation for human consumption and establish real demand.

The last speaker, Dr. Simone Angeloni presented on chemical characterization and extract evaluation of coffee silverskin and spent coffee grounds. He noted that both have application potential in the cosmetic and food industry, but require efficient methods to recover these compounds and produce extracts rich in bioactive compounds.

To sum up, the coffee plant offers much more than the well-known beverage made from the roasted beans. During its cultivation, production, roasting and consumption, a vast amount of by-products are accumulated. Only a small fraction are currently used, mostly as fertilizer or as an energy source. But the majority that remains is either improperly used or, in the worst case, simply becomes waste.There is huge potential for innovation that would utilize all these waste and by-products. Such innovations have the promise of mitigating some of the economic burdens small-scale farmers face when confronted with globally fluctuating coffee prices and increasing production challenges due to climate change. But there are also many opportunities for start-ups in the consuming world to take advantage of all that these coffee by-products have to offer.